POI's creator (Voyajo Team)
Castell Bryn Gwyn is a prehistoric site on the Isle of Anglesey, west of Brynsiencyn. It is a circular clay and gravel bank covered with grass, still some 1.5m high and revetted externally by stone walls, which surround a level area some 54 metres in diameter. Its name means 'White Hill Castle' (...) (from Wikipedia)